'I'm sorry', Facebook boss tells European lawmakers

Facebook chief Mark Zuckerberg apologised to the European Parliament today and said the social media giant is taking steps to prevent a repeat of a massive breach of users' personal data.

Zuckerberg also pledged to keep investing in Europe as he made the latest stop on a tour of contrition over the Cambridge Analytica scandal that began in the US Congress in April.

Zuckerberg told the livestreamed hearing in Brussels that it has become clear in the last two years that Facebook executives "haven't done enough to prevent these tools from being used for harm".

"And that goes for fake news, foreign interference in elections or developers misusing people's information. We didn't take a broad enough view of our responsibility," he said.

"That was a mistake, and I'm sorry for it." Facebook admitted that up to 87 million users may have had their data hijacked by British consultancy Cambridge Analytica, which worked for US President Donald Trump during his 2016 campaign.

The Silicon Valley giant has told the European Commission, the EU's executive arm, that the personal data of up to 2.7 million Europeans may have been sent inappropriately to Cambridge Analytica, which has since filed for bankruptcy in the US.

The Facebook chief welcomed the EU's sweeping new personal data protection rules, which come into effect in three days, saying that his website was adopting similar steps.

Zuckerberg said Facebook was bringing in new features including a special "clear history" button that would allow them to delete any cookies or browsing history details it stores.

He also told the leaders of the European Parliament's political groups that Facebook would make fresh investments to protect its users in the wake of the scandal.

"It's going to take time to work through all of the changes we must make. But I'm committed to getting it right, and to making the significant investments needed to keep people safe," he added.

"I expect this will significantly impact our profitability. But I want to be clear: keeping people safe will always be more important than maximising our profits."